I could use some advice on this. I have a full 1.5MB up/down

No matter if one person is here or 10, max rate at any given port is about 150 kB. I can't for the life of me find any configurations relating to traffic rates...

I am aware there is a manual for all the comedians out there, I'm asking here for a reason.

  • 3 people referring me to the bandwidth of a standard T1. I said I'm using 1.5MB, and I'm looking for an answwer regarding the Dell. I would vote everyone of you down
    – Seth
    Jun 25, 2012 at 12:42
  • 1
    another typical example of confustion between MB/S and Mb/S
    – Zapto
    Jun 25, 2012 at 12:46
  • @Seth - your mis-use of of the term 'termination' identifies you as a begineer - we were all beginners once but there's no need to get angry when hardened professionals give you good advise. For a start that switch can only present 10Mbps and 100Mbps links to your client machines, nothing in between - and given that knowledge your performance issue must be due to your upstream speed, given 1.5Mbps is very close indeed to that of a standard T1 (or low speed DSL) link then almost certainly you simply haven't bought enough bandwidth. So please don't get angry with those trying to help ok.
    – Chopper3
    Jun 25, 2012 at 12:57
  • 2
    The 3 answers you refer to were all made before you edited I have a full 1.5MB up/down flex T1 for I have a full 1.5MB up/down, so I think it's unfair to criticise the people providing factually correct information, which to me fully accounts for what you are seeing.
    – Bryan
    Jun 25, 2012 at 13:12
  • Well said Bryan - and given you can't have a 1.5MB T1 link (en.wikipedia.org/wiki/Digital_Signal_1) I think he's hopefully got the message - we may even see an apology but I'm not holding my breath for that.
    – Chopper3
    Jun 25, 2012 at 13:23

4 Answers 4


Your T1 has a maximum raw line rate of 1,544Kb/s. There are 8 bits in a byte and 1,024 bytes in a kilobyte, so that translates to 187KB/s. Of course, the line doesn't just carry the data of the file you're downloading, it also has to carry address and control information. 168KB/s is the highest I've ever seen on a T1.

  • 1
    Do you have a T1 or not? All the evidence you've presented suggests that you have a line with a line data speed of 1.5Mbps or so. This is how line speeds are normally measured, this explains the performance you are seeing, and that's the maximum a T1 is capable of. Jun 25, 2012 at 13:48

Uh, T1 speeds are 1.5Mbits/s, not MBytes. (1.544Mbits, of which only 1.536 are available, what with digital overhead and all.)

So divide by 8, which would give you a max theoretical throughput of 0.1875 MBytes, or 187.5 KB/s, consider packet overhead, network conditions and quality of the monitoring tools you're using to get "about 150 KB," and there you go.

Sounds like your T1 is performing at or around the bandwidth it should.


Make sure of units: 150 kiloBYTES per second = 1200 kiloBITS per second, or 1.2 megabits. That's slightly on the low side (~80% utilization) but within tolerance depending on measurement intervals, etc.


Your 3448P has the following performance capabilities, reference available at http://www.dell.com/us/en/bpi/networking/pwcnt_3448p/pd.aspx?refid=pwcnt_3448p&s=bpi

Switch Fabric Capacity 17.6 Gb/s

Forwarding Rate 13.1 Mpps

Up to 8,000 MAC Addresses

With that in mind, you should be able to achieve a full 100Mb transfer rate from port to port with that backplane and packet forwarding capabilities. If you can transfer data from a device connected from one port to a device on another port at ~12MB/sec, then there is nothing wrong with your switch and you should troubleshoot the upstream device performance.

What upstream service are you subscribed to?


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